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在真空度为10-5Pa下的液体电化学-飞行时间二次离子质谱联用技术研究
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作者 夏海伦 华鑫 龙亿涛 《分析化学》 SCIE EI CAS CSCD 北大核心 2019年第12期1887-1892,共6页
传统电化学检测手段致力于研究电活性物质在电极表面的电子转移过程,却很难获得关于电极-电解质界面分子水平的信息。在分子水平实现电化学氧化还原反应中间体的原位检测,对研究电化学反应机理具有重要意义。本研究以辅酶Q0(CoQ0)在金... 传统电化学检测手段致力于研究电活性物质在电极表面的电子转移过程,却很难获得关于电极-电解质界面分子水平的信息。在分子水平实现电化学氧化还原反应中间体的原位检测,对研究电化学反应机理具有重要意义。本研究以辅酶Q0(CoQ0)在金电极表面的氧化还原过程为研究模型,通过构建可用于高真空环境下使用的微流控电化学反应池,在真空度低于10^-5 Pa环境中实现液体电化学-飞行时间二次离子质谱(ToF-SIMS)联用。CoQ0及池体材料氮化硅在电极击穿前后的ToF-SIMS成像结果表明,此联用技术可用于高真空条件下液体样品的直接检测。由电化学工作站对微流控电化学池中的工作电极施加不同电压后,可检测到CoQ0、CoQ0H2及中间体的存在,其随电压相互转化关系与CoQ0在水溶液中的氧化还原行为一致。CoQ0及其还原产物的质谱信号强度的相对变化情况提供了电极表面CoQ0氧化还原过程的直接分子证据,进一步表明此联用技术在电极-电解质界面原位检测方面具有应用潜力,为电极表面电化学反应机理研究提供了更多信息。 展开更多
关键词 辅酶Q0 电极-电解质界面 原位电化学检测 飞行时间-二次离子质谱
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基于样本均衡与特征交互的通信网络故障预测方法 被引量:3
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作者 贾珺 冯春燕 +2 位作者 夏海轮 张天魁 李成钢 《北京邮电大学学报》 EI CAS CSCD 北大核心 2021年第6期59-66,共8页
通信网络故障预测数据集样本不均衡,影响故障预测的准确性,对此,提出了基于样本均衡与特征交互的通信网络故障预测方法.首先,将基于Wasserstein距离的梯度惩罚生成对抗网络(WGAN-GP)用于生成新的少数类样本,解决了告警数据集中存在的样... 通信网络故障预测数据集样本不均衡,影响故障预测的准确性,对此,提出了基于样本均衡与特征交互的通信网络故障预测方法.首先,将基于Wasserstein距离的梯度惩罚生成对抗网络(WGAN-GP)用于生成新的少数类样本,解决了告警数据集中存在的样本不均衡问题,并提出了嵌入记忆向量的特征生成卷积神经网络(M-FGCNN)模型.利用多层感知器和卷积神经网络加强特征间的交互,将告警领域专家经验与因子分解机模型结合生成新的告警特征;在模型的嵌入矩阵中加入记忆向量并改进了模型的损失函数,增强了模型的记忆性.在样本不均衡的公开数据集上进行实验的结果表明,引入WGAN-GP模型的方法比已有的样本均衡方法能生成质量更好的新数据.M-FGCNN模型比其他深度学习模型具有更好的通信网络故障预测性能. 展开更多
关键词 故障预测 深度学习 生成对抗网络
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Low-cost binding update scheme based on pointer forwarding in HMIPv6 network
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作者 LIU Yin-long ZENG Zhi-min +2 位作者 xia hai-lun ZHANG Tian-kui HAO xiao-yan 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2010年第3期73-77,共5页
By introducing a mobility anchor point (MAP), hierarchical mobile IPv6 (HMIPv6) reduces the binding update signaling cost associated with mobile IPv6, but there still exist deficiencies. For instance, a mobile node (M... By introducing a mobility anchor point (MAP), hierarchical mobile IPv6 (HMIPv6) reduces the binding update signaling cost associated with mobile IPv6, but there still exist deficiencies. For instance, a mobile node (MN) needs to orderly accomplish two binding updates with the MAP and home agent (HA) when the MN performs inter-MAP mobility. This results in a high signaling cost, thus affecting network performance. To reduce the inter-MAP binding update cost of idle MN in HMIPv6, an optimization scheme based on pointer forwarding with a threshold is proposed. The scheme can reduces the binding update cost of idle MN by using the binding update between MAP to replace several home binding updates. The signaling cost difference is derived by analyzing the cost of the basic scheme and the optimization scheme between two successive sessions. Simulation results show that, the optimization scheme can reduce the binding update signaling cost and improve the network performance as long as a suitable threshold is chosen. The discussions on the sensitivity of tele-parameters are also given. 展开更多
关键词 HMIPV6 绑定更新 网络性能 低成本 转发 指针 基础 移动IPV6
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Evolved data scheduling scheme based on layered P2P streaming in mobile network
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作者 xia hai-lun WANG Ning ZENG Zhi-min 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2012年第3期60-67,共8页
To relieve the negative effect brought by the intricate wireless network environment and unstable user behavior in layered mobile peer-to peer(P2P) streaming service, an evolved layered P2P (E-LP2P) data scheduling sc... To relieve the negative effect brought by the intricate wireless network environment and unstable user behavior in layered mobile peer-to peer(P2P) streaming service, an evolved layered P2P (E-LP2P) data scheduling scheme in the process of service delivery is introduced in this paper. The data in base layer is scheduled according to its importance in streaming play to guarantee the basic play of streaming. The data in enhancement layer is scheduled according to the characters of streaming data, including its position and amount in server peer set in a multiple tied way towards the data in enhancement layer. To cope with the layer jitter caused by the fluctuation of bandwidth, jitter prevent mechanism is used to adjust the highest layer dynamically during the process of data scheduling. Simulation results show that the E-LP2P can provide good quality of service(QoS) performance in terms of throughput, layer delivery ratio, server load and useless packet ratio. 展开更多
关键词 P2P流媒体 调度计划 移动网络 流媒体服务 演进 流媒体播放 服务器负载 调度方案
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A fuzzy logic cooperative MAC for MANET
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作者 WANG Zhao-xiang xia hai-lun DING Wei 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2008年第1期55-60,共6页
In both wireless local area networks (WLAN) and mobile ad hoc networks (MANET), the IEEE 802.11e medium access control (MAC) protocol is proposed for an effective quality of service (QoS) solution. A number of studies... In both wireless local area networks (WLAN) and mobile ad hoc networks (MANET), the IEEE 802.11e medium access control (MAC) protocol is proposed for an effective quality of service (QoS) solution. A number of studies have been done to enhance the performance of 802.11e in MANET by independently adjusting contention window (CW) size of each access category (AC) in every node. However, without the cooperation between the high priority flows and lower priority flows, the QoS goal of high priority flows cannot achieve effectively. In this article, a fuzzy logic based cooperative MAC protocol (FLCMAC) is proposed to cooperate amongst network flows and dynamically adjust access probability of each low priority flow affecting the high priority flows to satisfy their QoS requirement. The simulation results indicate that compared to the enhanced distributed channel access (EDCA) scheme of 802.11e, the FLCMAC consistently excels, in terms of throughput and delay under moderate and heavy background traffic both in single-hop and multi-hop scenarios. 展开更多
关键词 通信系统 通信协议 通信网络 无线通信
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